测试 gRPC 功能

Question

我有一个任务是使用Jest测试 gRPC 客户端调用功能。典型的 Node.js 函数如下所示：

client.authenticate(request, meta, (error, response) => {
   if (!error) {
      console.log('REPLY FROM SERVER: ', response)
   } else {
    console.error(error)
  }
})

过程调用是回调函数，正如我们所见，我无法将响应对象导出到外部变量。上面的函数是我需要测试的函数。我需要检查该函数是否已被正确调用。我该如何用玩笑来做到这一点？现在已经挣扎了一段时间了。

Answer 1

您可以使用jest.spyOn(object, methodName)来模拟client.authenticate。

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例如

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index.ts：

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import { client } from \'./client\';\n\nexport function main() {\n  const request = {};\n  const meta = {};\n  client.authenticate(request, meta, (error, response) => {\n    if (!error) {\n      console.log(\'REPLY FROM SERVER: \', response);\n    } else {\n      console.error(error);\n    }\n  });\n}\n

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client.ts：

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export const client = {\n  authenticate(request, meta, callback) {\n    console.log(\'real implementation\');\n  },\n};\n

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index.test.ts：

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import { main } from \'./\';\nimport { client } from \'./client\';\n\ndescribe(\'62214949\', () => {\n  it(\'should log correct response\', () => {\n    const mResponse = \'mocked response\';\n    const logSpy = jest.spyOn(console, \'log\');\n    jest.spyOn(client, \'authenticate\').mockImplementationOnce((request, meta, callback) => {\n      console.log(\'mocked implementation\');\n      callback(null, mResponse);\n    });\n    main();\n    expect(logSpy).toBeCalledWith(\'REPLY FROM SERVER: \', \'mocked response\');\n    expect(client.authenticate).toBeCalledWith({}, {}, expect.any(Function));\n  });\n\n  it(\'should handle error\', () => {\n    const mError = new Error(\'network\');\n    const logSpy = jest.spyOn(console, \'error\');\n    jest.spyOn(client, \'authenticate\').mockImplementationOnce((request, meta, callback) => {\n      console.log(\'mocked implementation\');\n      callback(mError);\n    });\n    main();\n    expect(logSpy).toBeCalledWith(mError);\n    expect(client.authenticate).toBeCalledWith({}, {}, expect.any(Function));\n  });\n});\n

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带有覆盖率报告的单元测试结果：

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 PASS  stackoverflow/62214949/index.test.ts (10.557s)\n  62214949\n    \xe2\x9c\x93 should log correct response (23ms)\n    \xe2\x9c\x93 should handle error (8ms)\n\n  console.log\n    mocked implementation\n\n      at CustomConsole.<anonymous> (node_modules/jest-environment-enzyme/node_modules/jest-mock/build/index.js:866:25)\n\n  console.log\n    REPLY FROM SERVER:  mocked response\n\n      at CustomConsole.<anonymous> (node_modules/jest-environment-enzyme/node_modules/jest-mock/build/index.js:866:25)\n\n  console.log\n    mocked implementation\n\n      at CustomConsole.<anonymous> (node_modules/jest-environment-enzyme/node_modules/jest-mock/build/index.js:866:25)\n\n  console.error\n    Error: network\n        at Object.<anonymous> (/Users/ldu020/workspace/github.com/mrdulin/react-apollo-graphql-starter-kit/stackoverflow/62214949/index.test.ts:18:20)\n        at Object.asyncJestTest (/Users/ldu020/workspace/github.com/mrdulin/react-apollo-graphql-starter-kit/node_modules/jest-jasmine2/build/jasmineAsyncInstall.js:100:37)\n        at resolve (/Users/ldu020/workspace/github.com/mrdulin/react-apollo-graphql-starter-kit/node_modules/jest-jasmine2/build/queueRunner.js:45:12)\n        at new Promise (<anonymous>)\n        at mapper (/Users/ldu020/workspace/github.com/mrdulin/react-apollo-graphql-starter-kit/node_modules/jest-jasmine2/build/queueRunner.js:28:19)\n        at promise.then (/Users/ldu020/workspace/github.com/mrdulin/react-apollo-graphql-starter-kit/node_modules/jest-jasmine2/build/queueRunner.js:75:41)\n        at process._tickCallback (internal/process/next_tick.js:68:7)\n\n       8 |       console.log(\'REPLY FROM SERVER: \', response);\n       9 |     } else {\n    > 10 |       console.error(error);\n         |               ^\n      11 |     }\n      12 |   });\n      13 | }\n\n      at CustomConsole.<anonymous> (node_modules/jest-environment-enzyme/node_modules/jest-mock/build/index.js:866:25)\n      at stackoverflow/62214949/index.ts:10:15\n      at Object.<anonymous> (stackoverflow/62214949/index.test.ts:22:7)\n\n-----------|---------|----------|---------|---------|-------------------\nFile       | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s \n-----------|---------|----------|---------|---------|-------------------\nAll files  |      90 |      100 |   66.67 |      90 |                   \n client.ts |      50 |      100 |       0 |      50 | 3                 \n index.ts  |     100 |      100 |     100 |     100 |                   \n-----------|---------|----------|---------|---------|-------------------\nTest Suites: 1 passed, 1 total\nTests:       2 passed, 2 total\nSnapshots:   0 total\nTime:        12.424s\n

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